This week we consider some of the research that has been conducted that is related to the formal understanding of distributed associative memories introduced last week. We move from Hebb's 1949 notion of the cell assembly to simulations that attempt to bring this theory to life. We also consider holographic memories and their relation to DAMs. Finally we consider biological mechanisms related to Hebbian synapses. For our in class activity after the lecture we will be using the R statistical programming language to draw pretty pictures for us so that we can gain some understanding about the geometry of learning in a distributed memory using either the Hebb or the Delta rule. The description of the activity, and the R scripts that we are going to use, are provided on the right.